In the field of protecting an electrical circuit, it is known to use a device or a protective electrical component capable of opening the electrical circuit when the latter is traversed by a fault current, such as an overload current or a short circuit current.
In this respect, several protection devices exist, such as fuses. In a known manner, a fuse is a dipole that uses the Joule effect of the electrical current traversing it in order, in case of overload, to cause an electrical conductor to melt that opens the electrical circuit and thus prevents the electrical current from circulating. The fuses are sized as a function of the intensity of the fault current that the system must protect, as well as its opening time. Pyrotechnic circuit breakers are also known, also called “pyroswitches”. One limitation of pyrotechnic circuit breakers at this time is their low capacity to cut high voltages, for example greater than 50 V. Indeed, during a cutoff under high-voltage, an electrical arc appears that may cause the device to explode. Furthermore, in order to guarantee the cutoff, the pyrotechnic short-circuits are often bulky.
In this respect, it is also known to use a hybrid protective device characterized by the placement of two protective electrical components in parallel, such as a fuse and a pyroswitch. U.S. Pat. No. 7,875,997-B1 describes one example of such a device. The placement of these two components in parallel provides many advantages. First, the pyroswitch not being as resistive as the fuse, the majority of the electrical current will circulate in the pyroswitch. When the protection is triggered under a fault current, the pyroswitch opens. The fuse still being closed at this stage, it short-circuits the pyroswitch, preventing an electrical arc from appearing within the latter. The current then circulates in the fuse, causing the latter to melt. Such a protective device can be used with high electrical voltages exceeding the limit voltage of the pyroswitch, up to a voltage level equivalent to the caliber of the fuse. Since the fuse experiences only low currents during normal use, it can be small, which reduces its cost and its cutoff time.
However, the pyroswitch must have a command circuit able to supply the cutoff command. Such a command circuit may be complex and for example include a current sensor, a data processing unit and a microcontroller. Thus, the command circuit must be powered by an outside power source. The hybrid protection device, made up of the fuse, the pyroswitch and its command circuit, is not autonomous, and despite lower costs for the fuse, such a device creates a higher cost and bulk, in particular due to the outside supply source.